A Vehicle Key Tracking System Based on NLOS Anchor Identification

The vehicle key tracking technology plays a crucial role in modern vehicles. It not only enhances the security of the vehicle but also provides a more convenient user experience, making it an indispensable component of modern smart vehicles. This paper presents a vehicle key tracking system based on the identification of non-line of sight (NLOS) anchors, enabling more accurate tracking. The system first utilizes a direct positioning estimation (DPE) algorithm to estimate the target's position, followed by calculating the distances between the estimated position and anchors. These distances are then compared with the actual measurement data to determine an appropriate threshold for distinguishing between NLOS and LOS signals, with the ranging results from LOS signals used for tracking. Finally, the system was tested using a software-defined radio (SDR) platform. Experimental results demonstrate that the proposed algorithm achieves a median tracking error of 0.24 meters, compared to a median tracking error of 12 meters when tracking without using the NLOS identification algorithm. Furthermore, the 90 % tracking error for the circular trajectory is 0.72 meters.